Engine stalls at idle speed or stalls after the
start Vehicle has no idle speed
Coking causes the piston in the idle stabilization valve -N71 to jam.
Models affected: ABK engine from MY 95
Service: The idle stabilization valve -N71 should be checked
according to the workshop manual. If the valve sticks: Attach the
modification kit for changing the air intake point for the idle
stabilization valve - Part No. 048 198 455. Replace the idle
stabilization valve -N71 - Part No. 048 133 455
Idle speed which is either fluctuating or excessive
The idle speed components are lacking electronic adjustment after a
voltage loss in the system (for example after the disconnection of the
battery, control unit change and a problem with the voltage).
Models affected: ABK, ABC engine
Referring to the workshop manual do a basic setting with V.A.G 1551 .
Throttle valve potentiometers and idle stabilization valves have been
unnecessarily changed too often because of lacking system adjustment. If
the complaint is not corrected with the basic setting, then a component
is defective. It must be located by referring to the workshop manual.
Engine stalls sporadically when disengaging
clutch after overrun/in warm weather
Current engine adjustment.
After the overrun phase (overrun cut off), the fuel injection doesn't
restart in time whilst in warm weather the air conditioning compressor
is switched on.
Models affected: V6, 2.6 l, 2V, ABC engine, manual gearbox with
air conditioning from MY 96 Optimized engine adjustment with engine
Part No. 4A0 907 473 K or 4A0 907 473 L.
From Chassis No.:
4A VN 063 250
8D VA 219 000
8G VN 006 500
1. With optimized adjustment fit engine control unit.
2. (Vehicles without traction slip control) Part No. 4A0 907 473 K
3. (Vehicles with traction slip control) Part No. 4A0 907 473 L Only
vehicles of MY 96: The relay for lambda sensor heating -J278 has been
fitted should be investigated. Take away the relay for lambda sensor
heating -J278 (if fitted) and bridge the contacts 30 and 87 to close the
circuit. Position 1 on 3 connection carrier in the plenum chamber for
installation location A4 (8D). Position 1 on 6 connection carrier on the
passenger side of the A pillar for installation location A6 (4A):.
Position 14 on 13 connection carrier under the passenger storage box for
installation location Cabriolet:. Please Note: The control unit must be
coded after the installation Workshop Manual MPFI Injection and Ignition
Poor accelerator response or the engine stalls
when in the warming up stage whilst being stationary at traffic lights
In the control unit the cold initial running set is too thin.
Models affected: AHL engine
Part No. 3B0 907 557 A for improved control unit.
Identification on the sticker "5WP4351", data version "D05".
Wavering idle speed with cold/warm engine.
A smaller vacuum hose branches off from the crankcase ventilation, which
is routed as bypass around the throttle valve. Especially in winter the
throttle hose and/or the vacuum hose can become clogged and/or iced up
with crankcase condense water. Consequently the idle speed wavers by
several 100 rpm during the phase of warming up, gradually dying down as
the engine heats up. Pulsations in the air inlet hose are possible
through the crankcase ventilation.
This leads mainly to wavering idle speed with switched on electrical
consumers and air conditioning with a warm engine.
Models affected: ADP engine 1.6 l
Take away the intake hose complete with crankcase ventilation hose and
vacuum hose. Clean the throttle hole, 2 mm (4) diameter, and hose of the
vacuum (3). Take away the cylinder head cover, put in the new oil splash
guard and get rid of the old one - Part No. 06A 103 544 - (unscrewed).
Adjust the cylinder head cover and intake hose. Do not lose the O ring
and make sure it doesn't lose itself in the neck of the crankcase
ventilation hose. A tiny wavering of idle speed by approx. 50 rpm when
the vehicle is still rolling and the clutch is pressed down is no cause
for concern and is normal.
When cold or even just after more than 20 seconds
or so the engine doesn't start.
There is a vehicle breakdown and no fault is stored in the fault memory.
Models affected: ACK engine (142 kW) from MY 96
1. Look at the fault memory of the engine control unit. Investigate the
vehicle according to the workshop manual if a fault has been stored.
2. See if the basic setting of the throttle valve control unit is
correct, if necessary reset it.
3. If the basic setting is all right and if no fault has been stored,
take out the spark plugs and clean them, then replace.
4. Part No. 4D0 907 551 B - with data version D09 - Fit control unit.